The KneeAlign® system is a computer-controlled system intended to assist the surgeon in determining reference alignment axes in relation to anatomical structures during stereotactic surgical procedures. The KneeAlign system facilitates the accurate positioning of implants and instrumentation, relative to these alignment axes.

Orthopedic surgical procedures include but are not limited to:

· Total Knee Arthroplasty
· Unicompartmental Knee Arthroplasty Tibial Transverse Resection

Device Description

The KneeAlign® 2 System is a non-invasive computer assisted surgical navigation system for use in knee arthroplasty procedures. The KneeAlign® 2 System is configured to detect, measure, and display angular and positional measurement changes in a triaxial format.

The KneeAlign® 2 System utilizes a palm-sized computer module and reference sensor to generate positional information in orthopedic procedures providing a sequence of steps for registration of anatomical landmarks, calculation of mechanical axes, and positioning of instruments relative to the mechanical axes.

In total knee arthroplasty procedures, the device assists the surgeon in:

. Establishing the mechanical axis of the femur, determining the varus/valgus angle and the flexion/extension angle of the cutting block relative to the femur.
Establishing the mechanical axis of the tibia, determining the varus/valgus . angle and the posterior slope angle of the cutting block relative to the tibia.

In unicompartmental knee arthroplasty procedures, the device assists the surgeon in:

Establishing the mechanical axis of the tibia, determining the varus/valgus . angle and the posterior slope angle of the cutting block relative to the tibia, for the transverse resection.
The KneeAlign® 2 System comprises a single use computer module and reusable instrumentation.

AI/ML Overview

Acceptance Criteria and Study for KneeAlign 2 System

This device, the KneeAlign 2 System, is a computer-assisted surgical navigation system. Based on the provided FDA 510(k) summary, the substantial equivalence to predicate devices (KneeAlign 2 System K103829 and OrthAlign Plus System K153237) is demonstrated through technological comparison and performance testing. The key addition to the subject device is the ability to navigate tibial transverse resections in unicompartmental knee arthroplasty.

1. Table of Acceptance Criteria and Reported Device Performance

The FDA summary does not explicitly list quantitative "acceptance criteria" for accuracy performance in a tabular format with corresponding "reported device performance" values. Instead, it states that "System accuracy testing: bench testing with mechanical fixtures and foam models to verify navigated resection plane angular and depth accuracy" was performed.

For the purpose of this request, we can infer the acceptance criteria for the added functionality (tibial transverse resection in unicompartmental knee arthroplasty) by the assertion that the device is "as safe and effective as the predicate devices." The predicates were already cleared for their accuracy. Since the only performance data mentioned directly relates to this specific functionality, the "acceptance criteria" here is met by demonstrating the system's ability to accurately navigate these resections.

Acceptance Criteria (Inferred)	Reported Device Performance
Navigated resection plane angular accuracy for tibial transverse resections in unicompartmental knee arthroplasty sufficient for intended use	"System accuracy testing: bench testing with mechanical fixtures and foam models to verify navigated resection plane angular and depth accuracy." The 510(k) states: "This testing regime demonstrates that the subject device is as safe and effective as the predicate devices. This testing regime demonstrates that the subject device is substantially equivalent to the legally marketed predicate devices, for its intended use in the accurate navigation of tibial resection planes in unicompartmental knee arthroplasty."
Navigated resection plane depth accuracy for tibial transverse resections in unicompartmental knee arthroplasty sufficient for intended use	(Same as above)
System hardware meets mechanical requirements	"System hardware verification/validation testing to ensure the instruments meet their mechanical requirements."
Instrumentation cleaning, sterilization, and shipping validations met	"Instrumentation cleaning, sterilization and shipping validations for the specified processes."
Navigation device sterilization, packaging, shelf life, environmental conditions, and shipping validations met	"Navigation device sterilization, packaging, shelf life, environmental conditions and shipping validations for the specified ranges of conditions involved in each process. (Summary data for the identical predicate device is referenced.)"
System components biocompatibility meets ISO 10993-1 (2009)	"System components biocompatibility assessment per ISO 10993-1 (2009)."
Customer requirements / usability validation in cadaver with an advising surgeon meets design input requirements in a simulated use environment	"Customer requirements / usability validation in cadaver with an advising surgeon to validate the system meets design input requirements for its functions in a simulated use environment."

2. Sample Size Used for the Test Set and Data Provenance

Sample Size: The document mentions "bench testing with mechanical fixtures and foam models" for accuracy testing. It does not provide specific numerical sample sizes for these tests (e.g., number of resections, number of models). For the simulated use testing, it refers to a "prospective cadaver validation" but again, no specific number of cadavers is given.
Data Provenance:
- Country of Origin: Not explicitly stated, but given the company (OrthAlign, Inc.) is based in Aliso Viejo, California, USA, and the submission is to the U.S. FDA, it is highly likely the testing was conducted in the USA.
- Retrospective or Prospective: The cadaver validation was "prospective." The bench testing with foam models would also be considered prospective as it involves specifically designed tests for the purpose of validation.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

Number of Experts: For the "Customer requirements / usability validation," it states "with an advising surgeon." This implies at least one surgeon was involved in the simulated use ground truth establishment.
Qualifications of Experts: The qualification mentioned is "surgeon." No further details on years of experience, sub-specialty, or board certification are provided in this summary.

4. Adjudication Method for the Test Set

The document implies that the ground truth for "customer requirements/usability" was established by a single "advising surgeon" during the cadaver validation. There is no mention of an adjudication method involving multiple experts (e.g., 2+1, 3+1). For bench testing, the "ground truth" would be the known and controlled parameters of the mechanical fixtures and foam models.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance

No, an MRMC comparative effectiveness study was not done. This device is a surgical navigation system, not an AI diagnostic tool primarily aimed at improving human reading proficiency for imaging. The performance testing focuses on the device's accuracy in assisting the surgeon with measurements and positioning during a procedure, not on radiologists interpreting images.

6. If a Standalone (i.e., Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, in essence, standalone performance (in a controlled environment) was done for accuracy. The "System accuracy testing: bench testing with mechanical fixtures and foam models to verify navigated resection plane angular and depth accuracy" evaluates the device's algorithmic and sensor performance independent of a live surgical scenario, under controlled conditions where the "ground truth" (correct angles and depths) is preset. The "human-in-the-loop" (a surgeon) is then involved in the usability and simulated use validation.

7. The Type of Ground Truth Used

Bench Testing: The ground truth for angular and depth accuracy was established through the known parameters of "mechanical fixtures and foam models." This represents a controlled, engineered ground truth.
Simulated Use (Cadaver Validation): The ground truth was established by the "advising surgeon" determining if the system "meets design input requirements for its functions." This is a clinical expert consensus/assessment ground truth within a simulated environment.

8. The Sample Size for the Training Set

This document is a 510(k) summary for a surgical navigation system, not an AI/machine learning device that typically requires a large 'training set'. The principles of operation are based on inertial sensors and calculation of spatial coordinates (not deep learning). Therefore, the concept of a "training set" for an algorithm to learn from data (as in AI) does not apply in the context of this device's validation as described. The device utilizes algorithms based on established physics and geometry.

9. How the Ground Truth for the Training Set Was Established

As explained in point 8, the concept of a "training set" and its associated ground truth establishment is not applicable to the validation of this device as presented in the 510(k) summary. The algorithms are based on known mathematical principles for converting sensor outputs into spatial coordinates. Their accuracy is verified through empirical testing against known standards (bench testing), not "trained" on a dataset.

Summary

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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

March 2, 2017

OrthAlign, Inc. % David Vancelette Director QA/RA Orthalign, Inc. 120 Columbia, Suite 500 Aliso Viejo, California 92656

Re: K163379

Trade/Device Name: KneeAlign 2 System Regulation Number: 21 CFR 882.4560 Regulation Name: Stereotaxic Instrument Regulatory Class: Class II Product Code: OLO Dated: November 30, 2016 Received: December 1, 2016

Dear David Vancelette:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration. listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical devicerelated adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in

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the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely,

Mark N. Melkerson -S

Mark N. Melkerson Director Division of Orthopedic Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration

Indications for Use

Form Approved: OMB No. 0910-0120 Expiration Date: January 31, 2017 See PRA Statement below.

510(k) Number (if known)

K163379

Device Name KneeAlign 2 System

Indications for Use (Describe)

The Knee Align® system is a computer-controlled system intended to assist the surgeon in determining reference alignment axes in relation to anatomical structures during stereotactic surgical procedures. The KneeAlien system facilitates the accurate positioning of implants and instrumentation, relative to these alignment axes.

Orthopedic surgical procedures include but are not limited to:

· Total Knee Arthroplasty
· Unicompartmental Knee Arthroplasty Tibial Transverse Resection

Type of Use (Select one or both, as applicable)

Prescription Use (Part 21 CFR 801 Subpart D)

Over-The-Counter Use (21 CFR 801 Subpart C)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

This section applies only to requirements of the Paperwork Reduction Act of 1995.

DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.

The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:

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"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."

FORM FDA 3881 (8/14)

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5. 510(K) SUMMARY

This 510(k) summary is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92(c).

DATE	November 30, 2016
APPLICANT	OrthAlign, Inc.120 ColumbiaSuite 500Aliso Viejo, CA 92656Tel: (949) 715-2424Fax: (949) 831-9500
OFFICIALCORRESPONDENT	David VanceletteOrthAlign, Inc.120 Columbia,Suite 500Aliso Viejo, CA 92656dvancelette@orthalign.comTel: (949) 525-9034Fax: (949) 831-9500
TRADE NAME	KneeAlign® 2 System
COMMON NAME	Stereotaxic Instrument
DEVICECLASSIFICATION	Class II, 21 CFR §882.4560
PRODUCT CODES	OLO: Orthopedic Stereotaxic Instrument
PREDICATEDEVICES	OrthAlign Plus® System (K153237)KneeAlign® 2 System (K103829)
SUBMISSION TYPE	Traditional 510(k). The subject device is a modificationto the previously cleared KneeAlign® 2 System(K103829).

SUBSTANTIALLY EQUIVALENT TO:

The KneeAlign®2 System is substantially equivalent to the previously cleared KneeAlign® 2 System (K103829) and OrthAlign Plus® System (K153237).

DESCRIPTION OF THE DEVICE SUBJECT TO PREMARKET NOTIFICATION:

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format.

In total knee arthroplasty procedures, the device assists the surgeon in:

. Establishing the mechanical axis of the femur, determining the varus/valgus angle and the flexion/extension angle of the cutting block relative to the femur.
Establishing the mechanical axis of the tibia, determining the varus/valgus . angle and the posterior slope angle of the cutting block relative to the tibia.

In unicompartmental knee arthroplasty procedures, the device assists the surgeon in:

Establishing the mechanical axis of the tibia, determining the varus/valgus . angle and the posterior slope angle of the cutting block relative to the tibia, for the transverse resection.
The KneeAlign® 2 System comprises a single use computer module and reusable instrumentation.

INDICATIONS FOR USE:

The KneeAlign® 2 System has the same indications for use as the previously cleared KneeAlign® 2 System (K103829). Additional functionality has been added to the predicate device to enable the navigation of tibial transverse resections in unicompartmental knee arthroplasty. Also, Indications for Use are common to the OrthAlign Plus® System (K153237). Thus, the Indications for Use are as follows:

KneeAlign® 2 System:

The KneeAlign® system is a computer-controlled system intended to assist the surgeon in determining reference alignment axes in relation to anatomical structures during stereotactic orthopedic surgical procedures. The KneeAlign system facilitates the accurate positioning of implants and instrumentation, relative to these alignment axes.

Orthopedic surgical procedures include but are not limited to:

. Total Knee Arthroplasty
. Unicompartmental Knee Arthroplasty - Tibial Transverse Resection

TECHNICAL CHARACTERISTICS (COMPARED TO PREDICATE):

The KneeAlign® 2 System was cleared under K103829. The KneeAlign® 2 System comprises a single use computer module, a reusable reference sensor, a reusable femoral iig and a reusable tibial jig. The device utilizes algorithms to convert sensor outputs into spatial coordinates, providing graphical and numerical representation of instruments and

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anatomy on the user display screen. The KneeAlign®2 System is being updated to include navigation functionality for unicompartmental knee arthroplasty, as in the predicate device OrthAlign Plus® System (K153237). All other features and principles of operation remain unchanged.

PERFORMANCE DATA:

Device performance testing confirms that the KneeAlign® 2 System can be used according to its intended use. The KneeAlign® 2 System has been verified and validated according to OrthAlign's procedures for product design and development. Performance testing addressed only the added Unicompartments and surgical procedure steps. Performance testing included:

System hardware verification/validation testing to ensure the instruments meet . their mechanical requirements.
. Instrumentation cleaning, sterilization and shipping validations for the specified processes.
. Navigation device sterilization, packaging, shelf life, environmental conditions and shipping validations for the specified ranges of conditions involved in each process. (Summary data for the identical predicate device is referenced.)
System components biocompatibility assessment per ISO 10993-1 (2009). ●
Customer requirements / usability validation in cadaver with an advising ● surgeon to validate the system meets design input requirements for its functions in a simulated use environment.
. System accuracy testing: bench testing with mechanical fixtures and foam models to verify navigated resection plane angular and depth accuracy.

For simulated use testing, a prospective cadaver validation was done in a simulated operating room environment with a surgeon conducting the procedures.

This testing regime demonstrates that the subject device is as safe and effective as the predicate devices. This testing regime demonstrates that the subject device is substantially equivalent to the legally marketed predicate devices, for its intended use in the accurate navigation of tibial resection planes in unicompartmental knee arthroplasty.

The information provided by OrthAlign in this 510(k) application confirms that the KneeAlign® 2 System is substantially equivalent to predicate devices such as the KneeAlign® 2 System (K103829) and OrthAlign Plus® System (K153237).

BASIS FOR DETERMINATION OF SUBSTANTIAL EQUIVALENCE:

A technological comparison and bench and simulated use testing demonstrate the substantial equivalence of the KneeAlign® 2 System to the predicate devices.

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The subject device is identical to the predicate KneeAlign® 2 System (K103829), with the following exceptions:

The subject device allows for the navigation of the tibial transverse resection . plane in unicompartmental knee arthroplasty.
The subject device is substantially equivalent in terms of unicompartmental knee arthroplasty function to the predicate device OrthAlign Plus® System (K153237).

The table below summarizes the features of the subject device as compared to the predicate devices.

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510(K) SUMMARY

Table 1. KneeAlign® 2 System Comparison to Predicates

Property	KNEEALIGN® 2 SYSTEM	KNEEALIGN® 2 SYSTEM (K103829)PREDICATE 1	ORTHALIGN PLUS® SYSTEM (K153237)PREDICATE 2
Indications for Use	Total Knee Arthroplasty /Unicompartmental Knee Arthroplasty:The KneeAlign® system is a computer-controlled system intended to assist thesurgeon in determining referencealignment axes in relation to anatomicalstructures during stereotactic orthopedicsurgical procedures. The KneeAlignsystem facilitates the accurate positioningof implants and instrumentation, relativeto these alignment axes.Orthopedic surgical procedures includebut are not limited to:Total Knee Arthroplasty Unicompartmental KneeArthroplasty - TibialTransverse Resection	Total Knee ArthroplastyThe KneeAlign® system is a computer-controlled system intended to assist thesurgeon in determining referencealignment axes in relation to anatomicalstructures during stereotactic orthopedicsurgical procedures. The KneeAlignsystem facilitates the accuratepositioning of implants andinstrumentation, relative to thesealignment axes.Orthopedic surgical procedures includebut are not limited to:Total Knee Arthroplasty ▶ Unicompartmental KneeArthroplasty function is beingadded.	Total Knee Arthroplasty / Total HipArthroplasty / Unicompartmental KneeArthroplasty:The OrthAlign Plus®System is acomputer-controlled system intended toassist the surgeon in determiningreference alignment axes in relation toanatomical and instrumentationstructures during stereotactic orthopedicsurgical procedures. The OrthAlignPlus® System facilitates the accuratepositioning of implants, relative to thesealignment axes. The system aids thesurgeon in controlling leg length andoffset discrepancies in Total HipArthroplasty.Example orthopedic surgical proceduresinclude but are not limited to:Total Knee Arthroplasty Total Hip Arthroplasty:Anterior/Posterior Unicompartmental KneeArthroplasty: Tibial transverseresection ▶ Same Indications for Use.
Property	KNEEALIGN® 2 SYSTEM	KNEEALIGN® 2 SYSTEM (K103829)PREDICATE 1	ORTHALIGN PLUS® SYSTEM (K153237)PREDICATE 2
Technological Principles
Computer generation ofpositional information	Uses inertial sensors, microcontroller anddigital signal processor to generatepositional information.	Identical	Identical
Registration of anatomy	Lateral and medial malleoli and the centerof the tibial plateau are registered toestablish a tibial reference frame.	Identical	Identical
Navigation of tibialtransverse resection plane	Posterior slope is in the sagittal plan ofthe tibia. Varus/Valgus is in the coronalplane of the tibia.	Identical	Identical
Controls resection depth	Via mechanical instruments	Identical	Identical
Surgical work flow	Patient preparation Instrument setup Instrument attachment to patient Anatomic registrations Cutting block navigation Resection	Identical	Identical
Design Elements
Main System Components	Single-use computer unit Navigation software Reusable instrument set Registration instruments Cutting blocks	Identical	Identical
User Interface	Integrated graphical user interface, onsingle-use unit that attached toinstrumentation.	Identical	Identical
Tibial Cutting Blocks	Mechanical instrument that interfaceswith tibial jig for variable positioning	Identical	Identical

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Regulation Number and Section

§ 882.4560 Stereotaxic instrument.

(a)
Identification. A stereotaxic instrument is a device consisting of a rigid frame with a calibrated guide mechanism for precisely positioning probes or other devices within a patient's brain, spinal cord, or other part of the nervous system.(b)
Classification. Class II (performance standards).